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133 lines
3.3 KiB
133 lines
3.3 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* spu aware cpufreq governor for the cell processor |
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* |
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* © Copyright IBM Corporation 2006-2008 |
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* |
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* Author: Christian Krafft <[email protected]> |
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*/ |
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#include <linux/cpufreq.h> |
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#include <linux/sched.h> |
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#include <linux/sched/loadavg.h> |
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#include <linux/module.h> |
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#include <linux/timer.h> |
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#include <linux/workqueue.h> |
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#include <linux/atomic.h> |
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#include <asm/machdep.h> |
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#include <asm/spu.h> |
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#define POLL_TIME 100000 /* in µs */ |
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#define EXP 753 /* exp(-1) in fixed-point */ |
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struct spu_gov_info_struct { |
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unsigned long busy_spus; /* fixed-point */ |
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struct cpufreq_policy *policy; |
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struct delayed_work work; |
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unsigned int poll_int; /* µs */ |
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}; |
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static DEFINE_PER_CPU(struct spu_gov_info_struct, spu_gov_info); |
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static int calc_freq(struct spu_gov_info_struct *info) |
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{ |
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int cpu; |
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int busy_spus; |
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cpu = info->policy->cpu; |
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busy_spus = atomic_read(&cbe_spu_info[cpu_to_node(cpu)].busy_spus); |
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info->busy_spus = calc_load(info->busy_spus, EXP, busy_spus * FIXED_1); |
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pr_debug("cpu %d: busy_spus=%d, info->busy_spus=%ld\n", |
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cpu, busy_spus, info->busy_spus); |
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return info->policy->max * info->busy_spus / FIXED_1; |
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} |
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static void spu_gov_work(struct work_struct *work) |
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{ |
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struct spu_gov_info_struct *info; |
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int delay; |
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unsigned long target_freq; |
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info = container_of(work, struct spu_gov_info_struct, work.work); |
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/* after cancel_delayed_work_sync we unset info->policy */ |
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BUG_ON(info->policy == NULL); |
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target_freq = calc_freq(info); |
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__cpufreq_driver_target(info->policy, target_freq, CPUFREQ_RELATION_H); |
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delay = usecs_to_jiffies(info->poll_int); |
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schedule_delayed_work_on(info->policy->cpu, &info->work, delay); |
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} |
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static void spu_gov_init_work(struct spu_gov_info_struct *info) |
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{ |
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int delay = usecs_to_jiffies(info->poll_int); |
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INIT_DEFERRABLE_WORK(&info->work, spu_gov_work); |
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schedule_delayed_work_on(info->policy->cpu, &info->work, delay); |
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} |
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static void spu_gov_cancel_work(struct spu_gov_info_struct *info) |
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{ |
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cancel_delayed_work_sync(&info->work); |
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} |
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static int spu_gov_start(struct cpufreq_policy *policy) |
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{ |
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unsigned int cpu = policy->cpu; |
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struct spu_gov_info_struct *info = &per_cpu(spu_gov_info, cpu); |
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struct spu_gov_info_struct *affected_info; |
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int i; |
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if (!cpu_online(cpu)) { |
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printk(KERN_ERR "cpu %d is not online\n", cpu); |
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return -EINVAL; |
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} |
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if (!policy->cur) { |
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printk(KERN_ERR "no cpu specified in policy\n"); |
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return -EINVAL; |
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} |
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/* initialize spu_gov_info for all affected cpus */ |
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for_each_cpu(i, policy->cpus) { |
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affected_info = &per_cpu(spu_gov_info, i); |
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affected_info->policy = policy; |
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} |
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info->poll_int = POLL_TIME; |
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/* setup timer */ |
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spu_gov_init_work(info); |
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return 0; |
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} |
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static void spu_gov_stop(struct cpufreq_policy *policy) |
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{ |
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unsigned int cpu = policy->cpu; |
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struct spu_gov_info_struct *info = &per_cpu(spu_gov_info, cpu); |
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int i; |
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/* cancel timer */ |
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spu_gov_cancel_work(info); |
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/* clean spu_gov_info for all affected cpus */ |
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for_each_cpu (i, policy->cpus) { |
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info = &per_cpu(spu_gov_info, i); |
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info->policy = NULL; |
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} |
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} |
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static struct cpufreq_governor spu_governor = { |
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.name = "spudemand", |
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.start = spu_gov_start, |
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.stop = spu_gov_stop, |
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.owner = THIS_MODULE, |
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}; |
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cpufreq_governor_init(spu_governor); |
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cpufreq_governor_exit(spu_governor); |
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MODULE_LICENSE("GPL"); |
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MODULE_AUTHOR("Christian Krafft <[email protected]>");
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